Development and investigation of protective properties of the electromagnetic and soundproofing screen

We have developed a technology for manufacturing an universal electromagnetic and soundproofing screen based on foam-latex and foam-polystyrene. The dispersity and physical characteristics of components in a material for shielding electromagnetic field and noise have been investigated. The designed material consists of latex and iron ore dust with dominating dispersion of 12 µm. In order to improve the soundproofing properties, latex was supplemented during fabrication with a foam-forming agent − synthetic oleic acid. To reduce the weight, we added granulated foam-polystyrene with the size of granules 1−3 mm to the material. We examined screens with a thickness of 5 mm and 10 mm with a different content of the metallic substance. It was determined that the shielding coefficients of the material 5 mm think containing 5‒20 % of iron ore content are as follows: for electromagnetic field of frequency 2.4‒2.6 GHz ‒ 1.8−44; for the magnetic field of industrial frequency ‒ 1.2−15.0. For the material with a thickness of 10 mm they are 2.9−52.0 and 2.3‒38.4, respectively. The noise reduction index of 41−44 dB is achieved at noise frequencies of 6−8 kHz, which is the most critical for humans. The structural study of the materials' surface was performed. It has been established that at the content of the metallic substance above 15 %, its distribution in the bulk of the material becomes non-homogenous. In order to improve the efficiency of electromagnetic protection, it is expedient to produce a magnetic or rheological fluid from iron dust in advance, to apply it in the technological process for foam-latex fabrication. It has been proven that the combined electromagnetic and soundproofing (acoustic) screens, that are small in thickness and low in weight, could provide reduction of the levels of electromagnetic fields and noise to match the norms, which is especially important when they are applied in the transportat industry